A circuit for suppressing the second harmonic of an octave power amplifier
By designing a circuit including a CNC phase shifter and a frequency measurement system in an octave power amplifier, the phase difference is used to offset the harmonic component, and the problem of difficulty in second harmonic suppression in the prior art is solved, and the problem of different frequencies is realized effective harmonic suppression effect.
Patent Information
- Application Number
- CN201810774931.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2018-07-13
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2038-07-13
AI Technical Summary
The implementation of second harmonic suppression of octave power amplifiers is more difficult. The circuit composition of the prior art such as feedforward technology is complex and the degree of harmonic cancellation depends on the phase and amplitude alignment accuracy of the signal, so it is more difficult to implement it in detail.
Design a circuit including a first-stage amplifier, a power divider, a CNC phase shifter and a frequency measurement system, and use a CNC phase shifter to shift the output signal of the pre-stage amplifier to make the harmonic component and the fundamental signal in phase. On the contrary, the harmonic components of the last stage amplifier are offset in the last stage power amplifier, and the phase difference control is performed in combination with the frequency measurement system to adapt to signals of different frequencies.
The second harmonic suppression effect of the octave power amplifier is improved, so that harmonics can be effectively suppressed at any frequency, simplifying the circuit structure and improving the suppression accuracy.
Smart Images
Figure CN108649903B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of octave power amplifiers, and in particular to a circuit for suppressing the second harmonic of an octave power amplifier. Background Art
[0002] For octave power amplifiers, the second harmonic of the lower limit frequency just falls within the working frequency band, and it is impossible to achieve harmonic suppression by short-circuiting branches or filters. For this type of power amplifier, feedforward technology is currently mainly used to suppress harmonics at home and abroad. However, the circuit composition of feedforward technology is complex, and additional auxiliary power amplifiers are required. The degree of harmonic cancellation depends on the phase and amplitude alignment accuracy of the two signals, and its specific implementation method is relatively difficult. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide a circuit for suppressing the second harmonic of an octave power amplifier, thereby solving the problem that harmonic suppression is difficult to achieve.
[0004] The technical solution of the present invention to solve the above technical problems is as follows: a circuit for suppressing the second harmonic of an octave power amplifier, comprising a first-stage amplifier, a power divider, a digitally controlled phase shifter, a second-stage amplifier and a frequency measurement system, wherein the input end of the first-stage amplifier is a signal input end, the output end of the second-stage amplifier is a signal output end, the output end of the first-stage amplifier is connected to the input end of the power divider, the output end A of the power divider is directly connected to the digitally controlled phase shifter, the output end B of the power divider is connected to the digitally controlled phase shifter through the frequency measurement system, and the digitally controlled phase shifter is connected to the input end of the second-stage amplifier.
[0005] Based on the above technical solution, the present invention can also be improved as follows.
[0006] Further, the frequency measuring system includes a frequency measuring chip, the model of the frequency measuring chip is NC2106Q, the 36th pin of the frequency measuring chip is respectively connected to one end of the capacitor C6 and one end of the resistor R2, the other end of the capacitor C6 is connected to the output end B of the power divider, the other end of the resistor R2 is respectively connected to one end of the capacitor C4 and one end of the capacitor C5, the other end of the capacitor C4 and the other end of the capacitor C5 are connected to the ground, the 38th pin of the frequency measuring chip is connected to the ground through the capacitor C8, the 1st pin of the frequency measuring chip is connected to the ground through the capacitor C7, and the frequency measuring chip Pin 5 of the chip is respectively connected to one end of a capacitor C3 and one end of a resistor R1, the other end of the capacitor C3 is connected to a crystal oscillator with a frequency of 1000MHZ, the other end of the resistor R1 is respectively connected to one end of a capacitor C1 and one end of a capacitor C2, the other end of the capacitor C1 and the other end of the capacitor C2 are respectively connected to pin 3 of the frequency measuring chip and ground, pin 2 of the frequency measuring chip is connected to ground through a power supply, and pins 17, 18, 19, 21, 22, 23, 24 and 25 of the frequency measuring chip are all connected to a numerically controlled phase shifter.
[0007] Furthermore, the model of the power divider is NC6525C-0515.
[0008] Furthermore, the model of the first-stage amplifier is CG2H40010F, and the model of the second-stage amplifier is CG2H40045F.
[0009] Furthermore, the model of the digital controlled phase shifter is NC3229S-107PD.
[0010] The beneficial effect of the present invention is that: in the present invention, a digitally controlled phase shifter is used to perform a certain form of phase shift on the output signal of the front-stage power amplifier, so that its harmonic component is opposite to the fundamental signal in phase. At this time, the input signal of the final-stage power amplifier includes a harmonic injection signal with a phase opposite to the fundamental wave. After amplification, the signal can offset the harmonic component generated by the power amplifier itself, thereby achieving the purpose of improving the harmonic suppression of the octave power amplifier. By adding a frequency measurement system, the present invention can improve the second harmonic suppression of the power amplifier under any frequency input signal. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 This is a circuit diagram of the present invention. DETAILED DESCRIPTION
[0012] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.
[0013] like Figure 1As shown, a circuit for suppressing the second harmonic of an octave power amplifier includes a first-stage amplifier, a power divider, a digitally controlled phase shifter, a second-stage amplifier and a frequency measurement system. The input end of the first-stage amplifier is a signal input end, the output end of the second-stage amplifier is a signal output end, the output end of the first-stage amplifier is connected to the input end of the power divider, the output end A of the power divider is directly connected to the digitally controlled phase shifter, the output end B of the power divider is connected to the digitally controlled phase shifter through the frequency measurement system, and the digitally controlled phase shifter is connected to the input end of the second-stage amplifier.
[0014] In an embodiment of the present invention, the frequency measuring system includes a frequency measuring chip, the model of the frequency measuring chip is NC2106Q, the 36th pin of the frequency measuring chip is respectively connected to one end of the capacitor C6 and one end of the resistor R2, the other end of the capacitor C6 is connected to the output end B of the power divider, the other end of the resistor R2 is respectively connected to one end of the capacitor C4 and one end of the capacitor C5, the other end of the capacitor C4 and the other end of the capacitor C5 are connected to the ground, the 38th pin of the frequency measuring chip is connected to the ground through the capacitor C8, the 1st pin of the frequency measuring chip is connected to the ground through the capacitor C7, and the frequency measuring chip Pin 5 of the chip is respectively connected to one end of capacitor C3 and one end of resistor R1, the other end of capacitor C3 is connected to a crystal oscillator with a frequency of 1000MHZ, the other end of resistor R1 is respectively connected to one end of capacitor C1 and one end of capacitor C2, the other end of capacitor C1 and the other end of capacitor C2 are respectively connected to pin 3 of the frequency measuring chip and ground, pin 2 of the frequency measuring chip is connected to ground through a power supply, and pins 17, 18, 19, 21, 22, 23, 24 and 25 of the frequency measuring chip are all connected to the CNC phase shifter.
[0015] In the embodiment of the present invention, the model of the power divider is NC6525C-0515.
[0016] In the embodiment of the present invention, the model of the first-stage amplifier is CG2H40010F, and the model of the second-stage amplifier is CG2H40045F.
[0017] In the embodiment of the present invention, the model of the digital controlled phase shifter is NC3229S-107PD.
[0018] The specific working principle of the present invention is:
[0019] Since phase shifters, bridges, microstrip lines and other phase shifting devices have different electrical lengths at different frequencies, they will produce different phase shifts for signals of different frequencies. Assuming that the phase shifting device produces a phase shift of α for a signal with a frequency of f, it will produce a phase shift of 2α for a signal with a frequency of 2f. By using this characteristic to perform a certain phase shift on the output signal of the pre-stage driver, the fundamental wave and harmonics of the input final stage power amplifier can have a certain phase difference, thereby canceling out the harmonics generated by the power amplifier itself and suppressing the second harmonics of the power amplifier.
[0020] In order to make the harmonic suppression circuit applicable to the ultra-wideband frequency range, the input signal can be frequency-detected, and the phase shift device can be controlled by the frequency measurement system so that the injection signal of the final power amplifier has a corresponding phase difference at different frequencies. The circuit has the ability of frequency adaptation and can suppress the second harmonic of signals of any frequency.
[0021] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A circuit for suppressing the second harmonic of an octave power amplifier, characterized in that: The invention comprises a first-stage amplifier, a power divider, a digitally controlled phase shifter, a second-stage amplifier and a frequency measuring system, wherein the input end of the first-stage amplifier is a signal input end, the output end of the second-stage amplifier is a signal output end, the output end of the first-stage amplifier is connected to the input end of the power divider, the output end A of the power divider is directly connected to the digitally controlled phase shifter, the output end B of the power divider is connected to the digitally controlled phase shifter through the frequency measuring system, and the digitally controlled phase shifter is connected to the input end of the second-stage amplifier; the frequency measuring system comprises a frequency measuring chip, the model of the frequency measuring chip is NC2106Q, the 36th pin of the frequency measuring chip is respectively connected to one end of a capacitor C6 and one end of a resistor R2, the other end of the capacitor C6 is connected to the output end B of the power divider, the other end of the resistor R2 is respectively connected to one end of a capacitor C4 and one end of a capacitor C5, the other end of the capacitor C4 and the other end of the capacitor C5 are connected to ground, and the 38th pin of the frequency measuring chip is connected to the ground through the capacitor C 8 is connected to ground, pin 1 of the frequency measuring chip is connected to ground through capacitor C7, pin 5 of the frequency measuring chip is respectively connected to one end of capacitor C3 and one end of resistor R1, the other end of the capacitor C3 is connected to a crystal oscillator with a frequency of 1000MHZ, the other end of the resistor R1 is respectively connected to one end of capacitor C1 and one end of capacitor C2, the other end of the capacitor C1 and the other end of the capacitor C2 are respectively connected to pin 3 of the frequency measuring chip and ground, pin 2 of the frequency measuring chip is connected to ground through a power supply, pins 17, 18, 19, 21, 22, 23, 24 and 25 of the frequency measuring chip are all connected to a digitally controlled phase shifter; the model of the power divider is NC6525C-0515, the model of the first-stage amplifier is CG2H40010F, the model of the second-stage amplifier is CG2H40045F, and the model of the digitally controlled phase shifter is NC3229S-107PD.